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I have twin GT35's in my 96 Fbody. They are VERY responsive. Forcefed also 'has had' or does have twins as well. I've had other issues that keep me from getting the car/;engine/trans dialed in (4L80E started slipping, put my old TH350 in but had a crap TC because PTC was backlogged, then had either head gasket or injector issues that burnt two pistons).
All that said,, the twins, using my self made hotside using two passenger side truck manifolds, light off real quick and traction on the street and the track is the real hold back. With the 4L80E and bone stock from TC to the internals(156K junkyard taken from the yard to my car with only a filter change), leaving the line at idle (because trying to foot brake just over powered the front tires/brakes and pushed my right thru the staging lights) it ran 133mph the first time out. The trans started progressively to slip under load so much that it was banging off the rev limiter a couple of times before every shift. I pulled it, put in the aforementioned built TH350 (which has a transbrake) . I wanted a PTC TC since the one I had previously worked VERY well but they had tons of orders ahead of me. I looked around for anyone selling one or something even close in quality but only had one respondent that had a 3200 stall "Boss Hog". It's more suited to a 350hp car but I wanted to drive my car before the summer was over, so I bought/installed it. Just as I feared, the engine just blew through the converter and as I watched the tach during the couple of passes on the first day out. The rpm's got up to 6,800 and when I shifted from 1st 2nd and from 2nd to 3rd, did not drop at all. Couple that with it blowing the tires of (Nitto 315x35x17's) off the line and spinning on the shifts, It was not a stellar day. Next, I tried my M/T ET streets. Same story on the spinning. Went and bought a pair of Hoosier 28" slicks and mounted them on my stock z28 salad shooter rims(16").
Went to the strip on a weatherwise, dicey day. Got one pass before it rained Next week, I went back and the first pass, it left well but by mid track, something felt 'funny' so I got off the throttle and coasted the rest of the way thru the track. As I turned of the track and onto the return road , it was obvious that the engine was hurt. I drove to the timing booth and picked up my slip. Well, I'll be, 10.3 at 123mph , having shut off earlier AND, to find out when I tore down the motor, pistons 4 and 6 had substantial pieces of the piston crowns GONE. So 10.3 , shutting off early and two burnt pistons. This was on pump 93, no meth, no alcohol, Dual 2.5" in/out Air to Air ebay intercooler. The cause of the burnt pistons is still not 100% clear. I thought perhaps those two injectors had failed in some way but when I sent them to Fuel Injector clinic , everything was working fine.. I checked the wiring harness but it's working fine too. Looks like it might have been a head gasket leak (LS9 gaskets) When I pulled the passenger side head I looked at the gasket but there wasn't any obvious "trenching" where you could point and say "Ah.. there's where it failed". The engine is rebuilt now and I just finished breaking it in.
As everyone says, boost is a multiplier, so if your unboosted (naturally aspirated engine) makes 300hp , boosting it to 14.5 would be 600hp and 30psi would be 900. I have no doubt you can make 900hp with the right combination of supporting parts (especially if running E85).
i have the same/similar turbos on a 5.3 with ls2 cam and they are lazier than i expected. 73 chevelle wagon full weight with manual trans. i havent messed with the car in a while so i dont remember off the top of my head but i think i was crossing 10psi at like 3800rpm
my turbos are t3 0.8 ar, cast compressor wheel.
i dont know how much power im making, but i think its quite a bit for the minimal tuning ive done. it was enough to shatter 3rd gear in an ar5 at 10psi.
im pretty sure a few years back a guy with a gto put down 800ish to the tire at 18 psi with the t4 6162s and the turbos were out of breath.
That's the ones I use also.. On3 T3 GT35's, .8 A/R Stainless Steel V-Band housings w/Cast wheels.
Originally Posted by TrendSetter
i have the same/similar turbos on a 5.3 with ls2 cam and they are lazier than i expected. 73 chevelle wagon full weight with manual trans. i havent messed with the car in a while so i dont remember off the top of my head but i think i was crossing 10psi at like 3800rpm
my turbos are t3 0.8 ar, cast compressor wheel.
i dont know how much power im making, but i think its quite a bit for the minimal tuning ive done. it was enough to shatter 3rd gear in an ar5 at 10psi.
im pretty sure a few years back a guy with a gto put down 800ish to the tire at 18 psi with the t4 6162s and the turbos were out of breath.
mine are ebay gt3582s with vband downpipe. i tried to find them and all i see now are billet wheel ones. i believe i paid about 200 each for them. im still undecided whether i like them or not. i was hoping for a more responsive combo, but i think i have some work on my end before i judge the turbos too harshly.
The S366 are physically large. They are awesome units, but pricey as well. IMO the next stup up is a pair of 61/65 or 67/65 from VS racing. Wicked69 made close to 1000whp with them on a 6.0. They are great units and were about 300ish each last I checked. Call VS racing and ask. He will set you up.
I've seen 850whp on a set of cast GT35's on an LS1 (manual trans, dynojet) and 28lbs. turbos were beyond tapped and picked up very little power past 20psi.. Thats with the cast 61mm comp wheel. You can buy 64mm billet compressor wheel GT35's. (thats what I have) for about $250 each. They "should* hit your goal of 850-900 and stay compact and relatively quick spooling. Go for the T4 housings w a 900hp goal.
Alot of the spool speed will be dictated by the hotside/coldside piping size/volume and the tune. I see you have large diameter Ebay manifolds. That's already a strike against you IMO. a factory manifold will retain heat better and keep velocity up. Not to mention take up less space and make plug changes a breeze. They will work, don't get me wrong. Just not my preference. They melt plug wires and make everything more difficult.
The S366 are physically large. They are awesome units, but pricey as well. IMO the next stup up is a pair of 61/65 or 67/65 from VS racing. Wicked69 made close to 1000whp with them on a 6.0. They are great units and were about 300ish each last I checked. Call VS racing and ask. He will set you up.
I've seen 850whp on a set of cast GT35's on an LS1 and 28lbs. turbos were beyond tapped and picked up very little power past 20psi.. Thats with the cast 61mm comp wheel. You can buy 64mm billet compressor wheel GT35's. (thats what I have) for about $250 each. They "should* hit your goal of 850-900 and stay compact and relatively quick spooling. Go for the T4 housings w a 900hp goal.
Alot of the spool speed will be dictated by the hotside/coldside piping size/volume and the tune. I see you have large diameter Ebay manifolds. That's already a strike against you IMO. a factory manifold will retain heat better and keep velocity up. Not to mention take up less space and make plug changes a breeze. They will work, don't get me wrong. Just not my preference. They melt plug wires and make everything more difficult.
they spool up fine especially since my convertor is a 3800 flash. It’s instant boost when I stomp it. At 7psi 10.5 aft with 9 degrees timing on my terminator x it felt faster than my 4.6 mod motor at 700whp transmission and convertor make a huge difference.
the spool isn’t a problem just wondering if they are gonna tap out too early. The motor is .30 over now and a little higher comp so spooling won’t bother me. I’m glad y’all say they can hit my goal. And I will look into the vs racing turbos also for when I upgrade. I mounted the coils back and under in the frame rails so the plug wires are gonna be good.
might have to goto the bigger turbos to get it to go down track lol
I have twin GT35's in my 96 Fbody. They are VERY responsive. Forcefed also 'has had' or does have twins as well. I've had other issues that keep me from getting the car/;engine/trans dialed in (4L80E started slipping, put my old TH350 in but had a crap TC because PTC was backlogged, then had either head gasket or injector issues that burnt two pistons).
All that said,, the twins, using my self made hotside using two passenger side truck manifolds, light off real quick and traction on the street and the track is the real hold back. With the 4L80E and bone stock from TC to the internals(156K junkyard taken from the yard to my car with only a filter change), leaving the line at idle (because trying to foot brake just over powered the front tires/brakes and pushed my right thru the staging lights) it ran 133mph the first time out. The trans started progressively to slip under load so much that it was banging off the rev limiter a couple of times before every shift. I pulled it, put in the aforementioned built TH350 (which has a transbrake) . I wanted a PTC TC since the one I had previously worked VERY well but they had tons of orders ahead of me. I looked around for anyone selling one or something even close in quality but only had one respondent that had a 3200 stall "Boss Hog". It's more suited to a 350hp car but I wanted to drive my car before the summer was over, so I bought/installed it. Just as I feared, the engine just blew through the converter and as I watched the tach during the couple of passes on the first day out. The rpm's got up to 6,800 and when I shifted from 1st 2nd and from 2nd to 3rd, did not drop at all. Couple that with it blowing the tires of (Nitto 315x35x17's) off the line and spinning on the shifts, It was not a stellar day. Next, I tried my M/T ET streets. Same story on the spinning. Went and bought a pair of Hoosier 28" slicks and mounted them on my stock z28 salad shooter rims(16").
Went to the strip on a weatherwise, dicey day. Got one pass before it rained Next week, I went back and the first pass, it left well but by mid track, something felt 'funny' so I got off the throttle and coasted the rest of the way thru the track. As I turned of the track and onto the return road , it was obvious that the engine was hurt. I drove to the timing booth and picked up my slip. Well, I'll be, 10.3 at 123mph , having shut off earlier AND, to find out when I tore down the motor, pistons 4 and 6 had substantial pieces of the piston crowns GONE. So 10.3 , shutting off early and two burnt pistons. This was on pump 93, no meth, no alcohol, Dual 2.5" in/out Air to Air ebay intercooler. The cause of the burnt pistons is still not 100% clear. I thought perhaps those two injectors had failed in some way but when I sent them to Fuel Injector clinic , everything was working fine.. I checked the wiring harness but it's working fine too. Looks like it might have been a head gasket leak (LS9 gaskets) When I pulled the passenger side head I looked at the gasket but there wasn't any obvious "trenching" where you could point and say "Ah.. there's where it failed". The engine is rebuilt now and I just finished breaking it in.
As everyone says, boost is a multiplier, so if your unboosted (naturally aspirated engine) makes 300hp , boosting it to 14.5 would be 600hp and 30psi would be 900. I have no doubt you can make 900hp with the right combination of supporting parts (especially if running E85).
man thanks for the long story I like hearing all those details. How many pics were you running on 93? I ran 18 psi on my built mod motor on 93 hellion intercooler no meth and it was fine just kept timing under 11*
For sure not too small. I have twin gt35s from cxracing ($750) on my 5.3 with btr stage 2 cam on 93 pump. Made 656 on 5spd trans on 16psi. That was no meth.
i have M1 sprayed at 3psi + and my last dyno was 702rwhp at 18psi. They will just keep going I think for more power. Timing is at 14* from 3psi to 6700rpm.
That graph is slightly off because he rolled into rpms and let off then gassed it. Not sure why. So graph would be to left more. One below is old one before I had air fuels steady but shows the boost curve accurately.
10-04-2020, 04:03 PM
Twin turbo gt35’s too small? 
